Flushing journal buffers

During a successful normal shutdown, CICS® calls the log manager domain to flush all journal buffers, ensuring that all journal records are written to their corresponding MVS system logger log streams.

During an immediate shutdown, the call to the log manager domain is bypassed and journal records are not flushed. Therefore, any user journal records in a log manager buffer at the time of an immediate shutdown are lost. This does not affect CICS system data integrity. The system log and forward recovery logs are always synchronized with regard to I/O and unit of work activity. If user journal data is important, you should take appropriate steps to ensure that journal buffers are flushed at shutdown.

These situations and possible solutions are summarized as follows:

• In a controlled shutdown that completes normally, CICS ensures that user journals are flushed.
• Use a shutdown assist transaction. In a controlled shutdown that is forced into an immediate shutdown by a shutdown-assist transaction, the shutdown-assist transaction will flush the journal buffers before forcing an immediate shutdown.
• In an uncontrolled shutdown explicitly requested with the SHUT IMMEDIATE command, CICS does not flush buffers. To avoid the potential loss of journal records in this case, you can issue an EXEC CICS WAIT JOURNALNAME command at appropriate points in the application program, or immediately before returning control to CICS. (Alternatively, you could specify the WAIT option on the WRITE JOURNALNAME command.)